code: def process_element(self, value, ctx: "KeyedProcessFunction.Context"):
      result = "Current key: {}, orderId: {}, payAmount: {}, timestamp: {}".format(
          str(ctx.get_current_key()),
          str(value[1]),
          str(value[2]),
          str(ctx.timestamp()),
      )
      yield result
      current_watermark = ctx.timer_service().current_watermark()
      ctx.timer_service().register_event_time_timer(
          current_watermark + 1500
      )
  
file_path: flink/flink-end-to-end-tests/flink-python-test/python/datastream/data_stream_job.py
imports: from typing import Any
  from pyflink.common import Duration
  from pyflink.common.serialization import SimpleStringSchema
  from pyflink.common.typeinfo import Types
  from pyflink.common.watermark_strategy import TimestampAssigner, WatermarkStrategy
  from pyflink.datastream import StreamExecutionEnvironment, TimeCharacteristic
  from pyflink.datastream.connectors import FlinkKafkaProducer, FlinkKafkaConsumer
  from pyflink.datastream.formats.json import JsonRowDeserializationSchema
  from pyflink.datastream.functions import KeyedProcessFunction
  from functions import MyKeySelector
label_desc: Use image node_id 1 for calling the MyProcessFunction obj's underlying member method code with example usage: obj.process_element(value, ctx) without return types